There are a number of conditions which cause the muscle to contract, resulting in adverse reactions in the body. For instance, contraction of coronary arteries can cause severe chest pains, such as those experienced with angina pectoris. In addition, contraction of peripheral vasculature can result in hypertension.
In the case of angina pectoris, a common treatment is the placing of nitroglycerin under the tongue. This produces nitric oxide (NO) which is mediated by cyclic-3',5'-guanosin-monophosphate, resulting in dilation of the coronary arteries and relief of the symptoms. However, the body eventually develops a tolerance to nitroglycerin, thus rendering it ineffective.
There are many agents for treating hypertension but many problems are associated with their use. Some of them cause the patient to develop rashes in some cases. Other cause hypotension unless the dosage is controlled and monitored with great care.
Because of these problems with the agents of the prior art, the discovery of a new class of agents for relaxing smooth vascular muscle is beneficial.